The present invention relates to stump cutter disks which comprise a wheel on which cutting elements are mounted that grind-up stumps as the wheel is driven, and in particular to wear strips mounted on the wheel to minimize abrasive wear.
A stump grinding disc 100 disclosed in U.S. Pat. No. 6,382,277, and depicted herein in FIG. 1, includes a metallic wheel 112 which defines an axis of rotation. The wheel has a pair of parallel side surfaces 114 intersected by the axis A, and an outer circumferential edge surface 116 defining a largest diameter of the disk. The side surfaces 114 are spaced axially apart by a distance which is much shorter than a maximum diameter of the disk. A plurality of side cutting elements 120 are mounted on each side surface, and a plurality of peripheral cutting elements 122 are mounted in recesses 124 formed in the circumferential edge surface 116.
Stump cutter disks experience wear on the outer circumferential edge surface 116 of the disk, especially in the case of larger disks turning at high rpm. As the disk is lowered into the ground to cut a root ball, the roots and surrounding ground and rocks wear on the edge surface. The disk material is quickly eroded and its diameter is reduced, requiring that the disk be repaired or replaced. Both of those options are expensive and time consuming. To repair the disk, hard face material in the form of weld wire or rod is deposited on the circumferential edge using a welding machine. That requires many man-hours, and the hard face material is expensive. The repair is temporary and must be replaced as the disk wears down again.
To replace the disk, it must be removed from the machine, and all of the cutters must be removed and re-attached to a new disk. Some machine designs require that the cutter shaft be removed in order to change the disk. That often requires that the shaft bearings be replaced, which is expensive.
One attempt made to extend the life of stump cutters involved manufacturing the disk from an abrasive resistant material or work-hardened steel. Those materials are expensive and are difficult to machine and penetrate in order to form holes for the cutters. Moreover, the wear resistance offered by such disks is minimal and not very cost effective. Therefore, it would be desirable to provide a more effective and economical way of minimizing the rate of wear of a disk's outer surface.